This invention concerns a method for sheathing bales of plants, fodder or other, under a plastic film.
This invention also relates to the material used for sheathing bales of plants, fodder or other, under plastic film, round bales as well as parallelepipedic bales.
This material consists on the one hand of a storing and drawing frame for the plastic film in order to form a kind of funnel, as described in the document CA-111 546 for round bales and, on the other hand, loading means that enable placing the bales one after the other into said funnel.
The drawing frame is mounted on a carrier that is, moreover, suitably arranged upstream of said drawing frame, for accommodating, centring and guiding each bale as it is pushed into the funnel whose inlet is formed and held open with sufficient diameter by said drawing frame.
The carrier can be moved as the bales are inserted, as described in the document GB-2 227 220, by a step corresponding to the length of these bales, directly by the vehicle that handles the bales, i.e. a transport vehicle such as a farming tractor fitted for example with a loading arm or similar.
Handling these bales on the fields does not enable accurate positioning of the bales on the carrier or reliable sheathing; the latter operation calls for a certain skill on the operator""s part.
This invention suggests means that enable simplification of this sheathing operation and especially ensure fast execution of said operation.
Besides, the method according to the invention enables improvement of the compacting of the bales with respect to one another inside the sheath. Preferably, this sheath is made of plastic material; it is preferably stretched to enable insertion of the bales and then, after leaving the drawing frame, it resumes its normal position while compressing the periphery of the bales.
The sheathing method according to the invention using a sheath-carrier that moves as the sheath is being filled, consists:
in handling a bale by means of a transport vehicle fitted with a handling tool that is for instance equipped with spindles,
in laying the bale on the carrier, upstream of the plastic film storage supports making up said sheath,
in pushing the bale inside the sheath, resting against the previous bale,
in moving the carrier by a step matching the length of the bale, which operation that consists in pushing the bale uses the handling tool equipped to that effect with a pusher-ejector device whose movement causes, by reaction, the reverse motion of said vehicle by means of said handling tool, whereas said tool is arranged to drive and move the sheathing carrier simultaneously over a distance corresponding to the length of the bale laid last on said carrier.
This method enables using a relatively simple tool. The sheathing carrier does not need any permanent energy source. It has a passive role throughout the sheathing operation.
The invention also relates to the handling tool mounted on a vehicle such as a farming tractor or similar, for implementing the method, which tool comprises a frame on which is mounted at least a pair of spindles, a pusher-rejector integrated to the spindle-carrying frame, behind said spindles, which frame comprises fastening means to the three-point coupling system, at the front or the rear of the tractor or still, according to the situation, to the end of a loading arm with which said tractor is equipped.
According to a preferred embodiment of the invention, the pusher-ejector device consists of a pair of compasses retracted inside the frame of the handling tool and that extend under the effect of a hydraulic actuator, for instance, controlled form the tractor by the operator, the pair of compasses extend over a distance that is at least equal to the length of the bale, in order to eject said bale from the spindles and to move simultaneously by reaction, the tractor and the sheathing carrier by a step corresponding to the distance travelled by the pusher, i.e. at least the length of the bale ejected.
Still according to the invention, the pair of compasses consistxe2x80x94of a first leg whose length corresponds more or less to the width or the diameter of the bale, which leg is articulated at one of its ends on an axle integral with the spindle-carrying frame and, xe2x80x94of a second leg articulated at the other end of the first leg, and that is fitted at its free end, with a pusher centered more or less on the longitudinal axis of the tractor, which first leg is mobile under the effect of an actuator that is mounted don the spindle-carrying frame and this first leg causes, when moving, the second leg to extend so that said pusher remains more or less centered on said longitudinal axis throughout its travel.
Still according to the invention, the second leg extends using a chain or cable that winds around a pulley section that is centered on its axis of articulation, at the end of the first leg of the pair of compasses, which cable is integral at one of its ends, with said sector of the second leg and at its other end, with the spindle-carrying frame at one point selected to enable displacement of the pusher along the longitudinal axis of the tractor, i.e. along a line more or less on the middle vertical plane of the spindles, or still the middle vertical plane of the bale to be laid on the sheathing carrier and picked up by said spindles.
Under certain operating conditions, the cable of the pusher may become slack and leave its guiding system at the angle of the pair of compasses.
This invention suggests using a roller chain, a double chain for instance, to ensure extension of the pair of compasses, which double roller chain advantageously maintains high stiffness on a plane that is perpendicular to the axis of its rollers, i.e. on the extension plane of the pair of compasses, which plane is for example horizontal.
Still according to the invention, the spindle-carrying frame comprises at its lower section, a crosspiece in the form of a heel or shoe that, on the one hand, serves as a marker to the operator with respect to the ground, to enable accurate spindling of the bales and, on the other hand, serves as a coupling means for pulling the sheathing carrier, by reaction during the ejection of the bale pushed onto the spindles, which member co-operates to that effect with a stop integral with said carrier.
The invention also concerns the sheathing carrier for implementing the method, which carrier co-operates with the handling tool and comprises, upstream of the drawing frame, a kind of base plate consisting of the upstream section of the rails integral with the frame of said carrier, and that extend over a length equal to at least twice the length of a bale, which rails are cantilever at their downstream end, i.e. on the sheathing side, and they comprise a fixed or removable stop system at their upstream end that co-operates with the heel or shoe of said tool in order to move said carrier by reaction, when the bale is ejected by means of the pusher of said handling tool.
According to another embodiment of the invention, the position of the stop on the rails is adjustable to suit the length of the bales and these rails may also comprise a second stop arranged downstream, preferably removable to enable sheathing of the last bale for example; this second removable stop is situated at a distance from the upstream stop that is at least equal to the length of a bale.
Taking into account the size and the weight of the bales, the invention suggests a stop system that makes handling of the bales easier, and in particular their placement on the carrier.
To that effect, the carrier comprises an area for laying the bales in the form of a base plate, made preferably of two rails separated by a distance that corresponds more or less to the radius of said bales; these guiding rails are situated as low as possible with respect to the ground and are extended downstream of the base plate in order to form a tilted plane at the inlet of the carrier; the space between the upstream extensions of the rails is able to accommodate a plate that co-operates to guide the bales as they are positioned by the tractor and the tool associated with said tractor. This guiding plate is articulated around a transversal and horizontal axis arranged at the upstream end of the legs of the rails, maintained elastically in a protruding position and capable of being retracted automatically when a bale is inserted. This plate also serves as a stop system and co-operates with the handling tool. The latter comprises a crosspiece in the form of a heel or shoe that retracts the plate automatically, and the latter can play a warning role as it resumes its normal stop positions soon as the handling tool has reached its normal bale unloading position. In this position, the stop is interposed between the crosspiece of the frame of the handling tool and the tractor vehicle, which causes during the ejection of the bale, by simple reaction, i.e. when the pusher of said tool rests on the bale, the tractor and the carrier simultaneously to move back, whereas the tractor is pushed directly by the frame of the handling tool whereas the carrier is pulled by said frame thanks to the stop installed upstream of said carrier.
Such arrangement of the inlet of the carrier with a stop in the form of a guiding late, limits vertical displacement of the bale and of the handling tool to the strict minimum.
The frame of the handling tool comprises, on the side of the tractor vehicle, means that enable to fasten it directly to the three-point coupling system of said tractor, as well to the rear or to the front of the tractor according to the equipment of said tractor, or to a carrier device mounted at the front of said tractor.
Moreover, this handling tool may fit other bale handling means such as for instance a barrel-type loading device such as described in the document FR-2 530 117; in such a case, there are as many handling tools as bales, for example three tools arranged in a star pattern.
Still according to the invention, the upstream section of the rails carrying the stop, forms a kind of frame that is articulated on said rails or the chassis of the carrier, around a horizontal and transversal axis, which frame is foldable at a right angle and lockable in this retracted position by means of tension rods or similar and said chassis and said frame are arranged to enable fastening of said carrier to the conventional three-point coupling system of a tractor in order to move the carrier as required. In such a case, the handling tool can be placed on the carrier, to be transported by the latter.
According to another embodiment of the invention, the carrier comprises at the guiding rails, guides to protect the plastic film during the introduction of the bales, which guides also enable centering of the bales in the funnel formed by the plastic sheath stretched on the drawing frame arranged on the carrier.
Still according to the invention, the chassis of the carrier is arranged in order to place the guiding rails of the bales as close to the ground as possible. In their upstream section, the rails are situated at a height compatible with the normal lifting capacity of a tractor when the latter is fitted with a handling tool fixed directly to its three-point lifting system. In their downstream section, the rails are situated a few centimetres above the ground, no more than 10 cm, so that generally these rails form a guiding plane that delineates an angle S with respect to the ground of approximately 5 to 7xc2x0.
The equipment according to the invention is also advantageously compact. The length of the guiding rails of the bales, downstream of the stop, is approximately twice and a third of the bales.